Celestron 11055 User Manual

Celestial Photography     •     59

Only the CM-1400   is  equipped  with  a  removable  secondary  mirror  that  allows

you to convert your f/11 telescope into an f/2.1 imaging system capable of
exposure times 25 times shorter than those needed with a f/11 system!  Used with
Celestron’s PixCel CCD System, objects will be easily found due to the wide .36°
by .27° field of view provided.  With the optional Fastar lens assembly you can
easily convert your Fastar compatible telescope to f/2.1 prime focus use in a matter
of seconds.  Your telescope can now be used in many different f-number’s for CCD
imaging.  It can be used at f/2.1 (with optional Fastar Lens Assembly), f/7 (with the
optional Reducer/Corrector), f/11, and f/22 (with the optional 2x barlow) making it
the most versatile imaging system available today.  This makes the system ideal
for imaging deep-sky objects as well as planetary detail.  The key to the Fastar’s
versatility is the variety of different F-numbers in which it can be used.  Described
below is the significance of each F-number and the type of object best suited to
that kind of imaging.

The above figure shows how the secondary mirror is removed when using the
optional PixCel CCD camera at f/2.1 and the Fastar Lens Assembly (#94181).

Warning: The secondary mirror should never be removed unless installing the
optional Fastar Lens Assembly.  Adjustments to collimation can easily be
made by turning the screws on the top of the secondary mirror mount without
ever having to remove the secondary mirror (see Telescope Maintenance
section of this manual).

Secondary
Mirror

Secondary
Mirror
Retaining Ring

Corrector Plate

Secondary
Mirror Mount
Handle